Applying quantitative micro-Raman spectroscopy to analyze stone compositions extracted from ureteroscopic lithotripsy urine

Abstract Objective In this study we applied quantitative micro-Raman spectroscopy (MRS) in binary stone compositions extracted from ureteroscopic lithotripsy (URSL) urine. Urolithiasis is a severe disease with a great impact. For ureteral stone patients, a basket retractor is used to catch the stone for analysis when patients undergo URSL. However, this can cause potential ureteral-related complications. The identification of the composition of a urinary stone is important for metabolic evaluation, decision making, and diet control. In this study, we applied a quantitative MRS method in a clinical setting to measure the composition of binary urinary stones in urine extracted via URSL. Materials and Methods This study was approved by the Institutional Review Board of Taipei City Hospital, Taipei, Taiwan from November 2008 to November 2009. Urine samples from fragmented stone sites in the patients' ureters were collected via the URSL procedure by drawing at least 10 mL of urine with a syringe. The urine samples from 30 patients were analyzed using an MRS-based analysis method, both qualitatively and quantitatively. Results The post-URSL urine powder from the samples was successfully analyzed using a quantitative MRS-based method, which was based on a linear equation developed according to the ratios of the relative intensities of the Raman bands corresponding to binary mixtures of known composition. Fourteen urine samples from 30 patients disclosed binary composition, and the ratio percentages were obtained using the equation along with a quantitative MRS-based method. Conclusion We successfully applied the quantitative MRS-based method clinically to analyze the stone compositions extracted from URSL urine. This method decreases the need to use a basket to catch macrostones for Fourier transform infrared spectroscopy analysis, while also still providing quantitative and quantitative stone analysis information by using the microstones in urine.